function bar() {
    var myname = 'Ro9nin'
    let test1 = 100
    if (1) {
      let myname = 'damn'
      console.log(test);
    } 
  }
  function foo() {
    var myname = 'M3'
    let test = 2
    {
      let test = 3
      bar()    // bar() 不与let形成块级作用域，在foo()中执行
    }
  }
  var myname = 'shit'
  let test = 1
  foo()